Robert was in the scam.
Was his fake sister in the scam too??
And what about the girl the protagonist is married (fake marriage)? Is she in the scam too?
Yes. Certain scenes don't take place in order which is why you're probably thinking that. In the first scene (at dinner) that wasn't his wife, it was the secretary who would provide people with their jobs.
shareYour subject line does not relate to your message. I was expecting your explanation on how the scam worked. Here's my interpretation:
The scam worked because people would hear the incident and offer to pay for the 'married couple''s meal. But once they were in a very loud place (the karaoke club) and the other people were unable to hear their story, the scam did not work, hence why he got beaten up by the waiter. He and the secretary pretending to be his wife were involved in the scam. Robert was not part of the scam until the very ending of the film, when he is picked up from the street by the leader of 'Filantropica'.
Hope this clarifies the confusion.